Installation guide

30 Chapter 1. Red Hat Cluster Suite Overview

IP address to its physical device on the LVS router nodes, having more than two NICs is

not a requirement.

Using this topology, the active LVS router receives the request and routes it to the ap-

propriate server. The real server then processes the request and returns the packets to the

LVS router. The LVS router uses network address translation to replace the address of the

real server in the packets with the LVS routers public VIP address. This process is called

IP masquerading because the actual IP addresses of the real servers is hidden from the

requesting clients.

Using NAT routing, the real servers can be any kind of computers running a variety oper-

ating systems. The main disadvantage of NAT routing is that the LVS router may become a

bottleneck in large deployments because it must process outgoing and incoming requests.

1.8.3.2. Direct Routing

Direct routing provides increased performance beneﬁts compared to NAT routing. Direct

routing allows the real servers to process and route packets directly to a requesting user

rather than passing outgoing packets through the LVS router. Direct routing reduces the

possibility of network performance issues by relegating the job of the LVS router to pro-

cessing incoming packets only.